What type of attack has a program running on your server that bypasses authorization?

What type of attack has a program running on your server that bypasses authorization?

• Backdoor
• DDoS
• Phishing
• DoS 

 

EXPLANATION

When a program running on a server bypasses authorization, it is obvious that a back door attack is in progress.
Key Takeaway: In a back door attack, a program or service is placed on a server to bypass normal security procedures. A back door is a program that is designed to hide itself inside a target host. It allows the installing user access to the system at a later time without using normal authorization or vulnerability exploitation.

http://www.hbs.net/blog/december-2016/bypassing-security-controls-cyber-crime
https://www.incapsula.com/web-application-security/backdoor-shell-attack.html